The invention broadly relates to seating devices that may be converted between sitting and lying positions, and is specifically directed to a two section convertible frame intended for use with futons. A three section convertible frame is disclosed in the companion application described above.
The popularity of futons has increased over the past several years because they are relatively inexpensive while at the same time being capable of being used for both sitting and sleeping. This popularity has spawned considerable activity in the development of frames that are adapted for use with futons and which can be converted between sitting and sleeping positions. Thus, a single article of furniture may be used for both a sofa and a bed, which not only reduces the need for and cost of separate articles of furniture, but also permits a single room to provide both living and sleeping functions. Many such convertible frames are now commercially available which generally include back and seat sections that can be moved between sitting and sleeping positions, and these existing devices include a variety of mechanisms of varying degrees of complexity requiring various operations by the user during the converting process.
Currently available futon frames generally suffer with disadvantages in a number of broad respects. First, some lack in sturdiness and stability. It is obviously essential that any article of furniture that provides both sitting and sleeping functions will be used both day and night and will therefore be subject to greater wear. Many existing futon frames are not only manufactured from inexpensive materials, but also are not designed to withstand wear over extended use.
Another problem in the conversion mechanism of many existing futon frames is the need during the conversion process to perform an additional manipulative function or functions in order for the frame to reach the point of rigidity and stability. For example, after the back and seat sections have been moved to the sleeping position, in which they are both horizontally disposed, it is necessary with many prior art devices to make a further manipulation of one of the sections or the mechanism itself to lock both sections in place. The failure to do so may cause the sections to fold up when weight is placed on them.
Another disadvantage with existing convertible futon frames is the requirement either that more than one person be involved in the converting process, or that a single person move from position to position before the converting process can be completed.
Another problem with many existing futon frames is release of the back section by the conversion mechanism during conversion but before conversion is completed. This typically occurs as the seat section is lifted to initiate conversion, and as the back section is accordingly tilted toward horizontal from its upright position, it is released and falls by gravity, striking the frame. This causes stress to the frame which may eventually damage it. The problem may be overcome with the assistance of a second person, who must position himself/herself to catch the back section as it is released.
Yet another disadvantage with prior art devices is the difficulty in manufacturing. Because most futon frames are formed primarily from wooden components, many current designs include metal components for reinforcement purposes. This makes the manufacturing process more complex and increases the cost of the device through increased labor and more expensive parts. Further, convertible futon frames that use a number of metal components are less attractive from the aesthetic standpoint, and are therefore less desirable to consumers.
The inventive convertible futon frame solves most of these problems. The disclosed frame includes first and second arm or end frames that are interconnected by front and rear cross rails, resulting in a sturdy rectangular frame. Back and seat members are carried by this stationary frame for movement between sitting and lying positions. Each of these members is generally rectangular in the preferred embodiment having front and rear sides and opposed ends. Specifically, the back member includes pivot pins that project laterally outward from each end proximate its lower or front side, and which guidably slide in elongated horizontal grooves formed in the arm end frames. The back member is also supported by a pair of metal straps that are pivotally connected between each of its ends and each of the end frames.
The seat member is pivotally connected along its rear side to the front side of the back section by a pair of pivot pins that project laterally from each end of the back member and which are slidably retained in short grooves formed in the ends of the seat member, permitting relative linear as well as pivotal movement. Abutment members are secured to each end of member which engage the back seat member in the sitting position to prevent relative rotation to the open or sleeping position. The seat member may be moved linearly out of engagement with the abutment member by virtue of the pin/short groove relationship, which permits the seat and back members to be relatively rotated to the open or sleeping position.
Based on this unique construction, a single person may quickly and easily move the convertible frame from the sitting to the sleeping position and vice versa from a single standing position in the front of the frame. Further, because of the unique construction and position of the strap members, the seat and back members are both rigidly held in both the sitting and sleeping positions without additional detent or locking mechanisms. All that is necessary is for the user to grasp the front edge of the seat member in either the sitting or lying position, and to make relatively simple movements with the seat member from a single position that accomplish the desired objective. Further, downward pressure resulting from the weight of both the futon and the user tends to retain the back and seat members in the chosen position, resulting in greater support and stability but without adversely affecting subsequent operations to the opposite position.
The inventive convertible frame is also designed to distribute the forces generated over the various components during seating, sleeping and conversion between positions, which enables the device to operate with a minimum of components other than wood. Metal reinforcing plates are therefore unnecessary, which simplifies the manufacturing process and reduces the cost of manufacture, all without compromising rigidity and stability. The fact that the inventive frame can be fabricated predominantly from hardwood components results in a frame that is aesthetically pleasing and hence more attractive to purchasers.